Information processing apparatus and video signal output control method

ABSTRACT

A video signal output control method in an information processing apparatus which being to be locked to an external unit by a lock mechanism, the video signal output control method includes detecting the state of the lock mechanism, and stopping the output of the video signal to the external unit, when the lock mechanism is in the unlocked state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2005-204542, filed Jul. 13, 2005, theentire contents of which are incorporated herein by reference.

BACKGROUND

1. Field

This invention relates to an information processing apparatus capable ofoutputting an encrypted digital video signal and a video signal outputcontrol method.

2. Description of the Related Art

Presently, digital broadcasting is becoming mainstream in place ofanalog broadcasting. Digital-signal-recorded sources, such as DVDs, havebeen used. With the transition from analog to digital broadcasting, itis conceivable that digital signals will be output directly to a TV set.

In the case of digital output, since use of high-quality video contentis possible, it is necessary to strengthen copyright protection toprevent provided video content from being reproduced in an unauthorizedmanner or copied illegally. As digital content protection techniques,the HDCP (High-bandwidth Digital Content Protection System) standard hasbeen proposed.

The HDCP standard is a standard for transferring the video contentrequiring copyright protection safely in a digital video signaltransmission system. The HDCP standard prescribes specifications forauthentication between the transmitting unit and the receiving unit, thesharing of a key for authentication, the encryption of video signals tobe transmitted, and others.

In authentication in the HDCP standard or the like, a device key forauthenticating the other party's device individually by public keyencryption is used. If authentication is successful between thetransmitting unit and the receiving unit, the transmitting unit encryptsthe video signal using the device key and transmits the encryptedsignal. The receiving unit decrypts the received video signal using thedevice key. For example, a digital image transmitting apparatus using anauthentication method complying with the HDCP standard or the like hasbeen disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-314970.

When a notebook personal computer is used as an information outputapparatus, use of a docking station can be considered in order to outputa signal to a TV set. In a state where the personal computer isinstalled on the docking station and the encrypted video signal isoutput to the TV set, suppose the personal computer (or an informationprocessing apparatus) is removed from the docking station (or anexternal unit). In this case, there is a possibility that the personalcomputer will kept outputting the video signal.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A general architecture that implements the various feature of theinvention will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments of the invention and not to limit the scope of theinvention.

FIG. 1 is an exemplary view showing a notebook personal computer as aninformation processing apparatus according to an embodiment of thepresent invention and a docking station as an external unit;

FIG. 2 is an exemplary perspective view of the back side of thecomputer;

FIG. 3 is an exemplary perspective view showing a configuration of theback side of the docking station;

FIG. 4 is an exemplary view showing a state where the computer isinstalled on the docking station and the output image of the computer isallowed to be output on an external display;

FIG. 5 is an exemplary view showing a system configuration of thecomputer, docking station, and external display;

FIG. 6 is an exemplary block diagram to help explain ACPI and anexternal output function of the personal computer acting as aninformation processing apparatus of the embodiment;

FIG. 7 is an exemplary flowchart to help explain the procedure forprocessing when the computer is installed on the docking station;

FIG. 8 is an exemplary flowchart to help explain the procedure forprocessing when an external display is detected and the protectedcontent is output to the external display;

FIG. 9 is an exemplary flowchart to help explain the procedure forprocessing when the computer is removed from the docking station in themiddle of outputting the encrypted video signal;

FIG. 10 is an exemplary view showing a modification of the systemconfiguration of FIG. 5; and

FIG. 11 is an exemplary view showing another modification of the systemconfiguration of FIG. 5.

DETAILED DESCRIPTION

Various embodiments according to the invention will be describedhereinafter with reference to the accompanying drawings. In general,according to one embodiment of the invention, an information processingapparatus comprises a body which being to be locked to an external unitby a lock mechanism, a display controller which is provided in the bodyand generates a video signal, a control section which stops outputtingthe video signal generated by the display controller to the externalunit, when the lock mechanism is in the unlocked state.

First, referring to FIGS. 1 and 2, the configuration of an informationprocessing apparatus according to an embodiment of the present inventionwill be explained. The information processing apparatus is realized inthe form of a battery-powered portable notebook personal computer 10.

FIG. 1 is a perspective view of the notebook personal computer with itsdisplay unit opened and a docking station serving as an extended unit.FIG. 2 is a perspective view of the back side of the computer.

The computer 10 comprises a computer body 11 and a display unit 12. Adisplay device composed of an LCD (Liquid Crystal Display) 17 isincorporated in the display unit 12. The display screen of the LCD 17 ispositioned almost in the center of the display unit 12.

The display unit 12 is provided on the computer body 11 so as to becapable of rotating freely between the opened position and the closedposition. The computer body 11 has a thin box-like enclosure. On itstop, there are provided a keyboard 13, a power button 14 for turningon/off the power supply of the computer 10, and a touch pad 16.

When the computer 10 is installed on a docking station 200 serving as anexternal unit, a docking connector 201 provided on the docking station200 connects with a docking port 20 provided on the back side of thecomputer 10 shown in FIG. 2, which enables signals to be transmitted.

FIG. 3 shows a configuration of the back side of the docking station200. As shown in FIG. 3, the docking station 200 includes a PS/2connector 202, a USB (Universal Serial Bus) connector 203, a DVI(Digital Visual Interface) connector 204, a parallel connector 205, aLAN connector 206, and a lock mechanism 207. When the computer 10 isinstalled on the docking station 200, the computer 10 can be locked tothe docking station 200 by operating the lock mechanism 207.

As shown in FIG. 4, when the computer 10 is installed on the dockingstation 200, the docking station 200 is connected via a DVI cable to anexternal display 300 complying with the HDCP (High-bandwidth DigitalContent Protection) standard serving as an external display unit, whichenables the images created by the computer 10 to be displayed on theexternal display 300.

Next, referring to FIG. 5, the system configuration of the computer 10,docking station 200, and external display 300 will be explained.

As shown in FIG. 2, the computer comprises a CPU 111, a North Bridge112, a main memory 113, a GPU (Graphics Processing Unit) 114, a SouthBridge 119, a TV tuner 120 acting as a receiving section for receivingbroadcast program data, a BIOS-ROM 120, a hard disk drive (HDD) 122, anembedded controller/keyboard controller (EC/KBC) IC 124, a LANcontroller 126, and an I/O controller 127.

The CPU 111, which is a processor for controlling the operation of thecomputer 10, executes an operating system (OS) and various applicationprograms loaded from the hard disk drive 122 into the main memory 113.

The CPU 111 also executes a BIOS (Basic Input Output System) programstored in the BIOS-ROM 120. The BIOS-ROM 120 is a program for hardwarecontrol.

The North Bridge 112 is a bridge device for connecting a local bus ofthe CPU 111 with the South Bridge 119. The North Bridge 112 has a memorycontroller for performing access control of the main memory 113. Inaddition, the North Bridge 112 has the function of communicating withthe GPU 114 via an AGP (Accelerated Graphics Port) bus or the like.

The GPU 114 is a display controller for controlling the LCD 17 used as adisplay monitor of the computer 10 or the external display 300. The GPU114, which has a video memory (VRAM), generates, from the display datawritten in the video memory by the OS/application programs, a videosignal for forming display images to be displayed on the LCD 17 of thedisplay unit 12 or the external display 300.

The GPU 114 has a coder 115 for encrypting video data to follow the HDCP(High-bandwidth Digital Content Protection) standard. The coder 115 hasa first key ROM 116 in which a plurality of encryption keys to encryptvideo data.

The South Bridge 119, which controls each device on an LPC (Low PinCount) bus, includes an IDE (Integrated Drive Electronics) controller, aPCI (Peripheral Component Interconnect) controller, and a USB controllerwhich are for controlling the hard disk drive (HDD) 122 and optical diskdrive (ODD) 123.

The optical disk drive 123 is a drive unit for driving storage media,including a DVD and a CD. In addition, the optical disk drive 123 is adrive unit which writes data into an additionally writable opticalmedium, such as a CD-R or a DVD-R, and writes/erases data into/from arewritable optical medium, such as a CD-RW, a DVD-RW, or a DVD-RAM.

The LAN controller 126 for exchanging data with a device connected anetwork is connected via a PCI bus to the South Bridge 119.

The EC/KBC 124 is a one-chip microcomputer into which an embeddedcontroller for power management and a keyboard controller forcontrolling the keyboard (KB) 13 and the touch pad 16 are integrated.The EC/KBC 124 has the function of turning on/off the power supply ofthe computer 10 according to the user's operation of the power button 14by operating in cooperation with a power supply controller.

The EC/KBC 124 can detect the state (locked/unlocked) of the lockmechanism 207.

The I/O controller 127 has the function of exchanging data with a deviceconforming to the IEEE 1284 standard.

The external display 300 includes a decoder 301 for decoding the videosignal encrypted by the coder 115, a second key ROM 302 which stores anencryption key for decrypting the video signal, and an EEPROM 303 whichstores device information, including the resolution of the displayconforming to the DDC (Display Data Channel) standard and the refreshrate.

The docking station 200 has the function of transferring a video signalfrom the coder 115 to the decoder 301 of the external display 300, thefunction of transferring a control signal between the coder 115 and thedecoder 301, an I2C bus for transferring display information stored inthe EEPROM 303 to the EC/KBC 124 according to the DDC standard, a PS/2connector 202 to which a keyboard/mouse is to be connected, a USBconnector 203, a DVI connector 204, a LAN connector 206 which isconnected to the LAN controller 126 and into which one end of a LANcable is inserted, and a parallel connector 205 to which the I/Ocontroller 127 is connected and into which one end of a cable complyingwith the IEEE 1284 standard is inserted.

In the computer 10, a Microsoft operating system 140 with a system powersaving function known as ACPI (Advanced Configuration and PowerInterface) has been installed. The ACPI function is effective not onlyfor lengthening the battery driving time of a battery-powered notebookpersonal computer but also for reducing the AC power consumption of adesktop personal computer with no battery and performing its temperaturecontrol.

FIG. 6 is a block diagram to help explain the ACPI and external outputfunction of the personal computer acting as the information processingapparatus of the embodiment.

An application 142 on the operating system 140 accesses DirectShow 143via a kernel 141 and generates a reproduced signal from MPG-2 data usingthe function of DirectShow 143. The reproduced signal is supplied fromDirectShow 143 to the GPU 114. The GPU 114 encrypts the reproducedsignal and outputs the encrypted signal to a video signal output port20A included in the docking port 20.

When the computer 10 docks with the docking station 200, the EC/KBC 124can detect the state of the lock mechanism 207. The EC/KBC 124 has alock register 1241 into which the state of the lock mechanism 207 is tobe written. The EC/KBC 124 has the function of, when the lock mechanism207 is operated, informing a BIOS program 1211 via the South Bridge 119and North Bridge 112 of the state of the lock mechanism 207. The BIOSprogram 1211 has the function of informing a GPU driver 146 for drivingthe GPU 114 via an HCI (Host Controller Interface) 145 of the state ofthe lock mechanism 207 informed by the EC/KBC 124. The GPU driver 146has the function of, when the lock mechanism 207 is unlocked, requestingan ACPI driver 147 via the kernel 141 to stop the supply of a clocksignal from a clock generator 150 to the GPU 114.

The ACPI driver 147 rewrites an ACPI register 1131 provided in thememory 113 to do setting so as to stop the supply of the clock signal tothe GPU 114. The BIOS program 1211 has the function of enabling a clocksupply stop signal supplied from the South Bridge 119 to the clockgenerator 150, when the ACPI register 1131 is rewritten to do setting soas to stop the supply of the clock signal to the GPU 114. The clockgenerator 150 has the function of stopping the supply of the clocksignal to the GPU 114, when the clock supply stop signal is enabled.

Referring to FIG. 7, the processing when the computer 10 is installed onthe docking station 200 will be explained.

When the user installs the computer 10 on the docking station 200connected to the external display 300, and locks the lock mechanism 207,thereby securing the computer 10 to the docking station 200, the EC/KBC124 detects that the lock mechanism 207 is in the locked state (blockS1). The EC/KBC 124 interrupts and informs the BIOS program 1211 thatthe lock mechanism has been locked (block S2). Moreover, the EC/KBC 124writes in the lock register 1241 that the lock mechanism is in thelocked state (block S3).

Next, the procedure for processing when the external display 300 isdetected and the protected content is output to the external display 300will be explained with reference to FIG. 8. The protected content (orvideo source) includes broadcast program data received by the TV tuner120 or data reproduced from storage media by the optical disk drive 123.

If the power supply of the external display 300 is on, the EC/KBC 124recognizes the external display 300 (block S11) and acquires deviceinformation on the external display 300 stored in the EEPROM 303 (blockS12). The EC/KBC 124 interrupts and informs the GPU driver 146 via theHCI 145 of the acquired device information (block S13). The deviceinformation includes information about whether the external display 300is compatible with the HDCP.

The GPU driver 146 determines whether the lock mechanism 207 is in thelocked state, referring to the lock register 1241 (block S14). If thelock mechanism 207 is not in the locked state (No in block S14), the GPUdriver 146 stops the output of the video signal.

If the lock mechanism 207 is in the locked state (Yes in block S14), theGPU driver 146 determines whether the external display 300 is compatiblewith the HDCP (block S15). If the external display 300 is not compatiblewith the HDCP (No in block S15), the GPU driver 146 ends the process.

If the external display 300 is compatible with the HDCP (Yes in blockS15), the GPU driver 146 communicates with the GPU 114 and externaldisplay 300 using the encryption keys stored in the first key ROM 116and second key ROM 302, thereby carrying out an authenticating process(block S16).

After the authenticating process, the GPU driver 146 permits the coder115 to output the encrypted video signal to the decoder 301, therebytransferring the video signal (block S17).

As described above, with the lock mechanism 207 in the unlocked state,since the video signal is not output to the docking station 200, even ifthe computer 10 is removed from the docking station 200, the videosignal is not output, with the result that there is no possibility thatthe video signal will be copied.

Next, the procedure for processing when the computer 10 is removed fromthe docking station 300 in the middle of outputting the encrypted videosignal will be explained with reference to FIG. 9.

When the user unlocks the lock mechanism 207, the EC/KBC 124 detectsthat the lock mechanism 207 is in the unlocked state (block S21). TheEC/KBC 124 interrupts and informs the BIOS program 1211 that the lockmechanism 207 has been brought into the unlocked state (block S22). TheEC/KBC 124 writes in the lock register 1241 that the lock mechanism 207is in the unlocked state (block S23). The BIOS program 1211 interruptsand informs the GPU driver 146 via the HCI 145 that the lock mechanism207 has been brought into the unlocked sate (block S24). The GPU driver146 requests the ACPI driver 147 via the kernel 141 to stop the supplyof the clock to the GPU 114 (block S25). The ACPI driver 147 rewritesthe ACPI register 1131 to do setting so as to stop the supply of theclock to the GPU 114 (block S26).

The BIOS program 1211 reads in the setting written in the ACPI register1131 (block S27). The BIOS program 1211 instructs the South Bridge 119via the North Bridge 112 to enable the clock supply stop signal suppliedto the clock generator 150 (block S28).

The clock generator 150 detects that the clock supply stop signal hasbeen enabled and stops the supply of the clock signal to the GPU 114(block S29). The supply of the clock signal is stopped, preventing theGPU 114 from operating, which stops the video signal being output fromthe video signal output port 20A.

As described above, with the video signal being output, when the lockmechanism 207 goes into the unlocked state, this prevents the videosignal from being output to the docking station 200. As a result, evenif the computer 10 is removed from the docking station 200, there is nopossibility that the video signal will be copied, because the videosignal is not output.

Moreover, the supply of the driving voltage to the GPU 114 may bestopped to prevent the video signal from being output from the videosignal output port 20A. In addition, the video signal may be preventedfrom being output from the video signal output port 20A by providing aswitching element between the video signal output port 20A and the GPU114 and controlling the switching element.

As shown in FIG. 10, the coder 115 and first key ROM 116 may not beincluded in the GPU 114. In this case, as for the low-speed controlsignal, an 8-bit parallel bus or UART may be used in place of the I2Csignal.

In the case of the computer 10 using an external coder shown in FIG. 10,since its configuration has a greater risk than that of FIG. 5, it isconceivable that the configuration will also be applied to a casewithout the docking station. That is, in place of an undock event, asignal indicating that the enclosure of the computer 10 is opened (oropen) may be used. Since the technique for detecting that the enclosureof the personal compute is opened has been known, an explanation anddrawing of the technique will be omitted.

While in the configuration of FIG. 5, two independent I2C buses havebeen provided, they may be integrated into one bus as shown in FIG. 11.In that case, it is necessary to make sure that the bus transfer speedis sufficiently fast for the control signals and the like.

In FIG. 5, since the docking station 200 is originally provided with amechanism and a circuit which generate an undock event, use of themechanism and circuit makes it possible to detect that the connectionbetween the notebook personal computer 10 and the docking station 200 iskilled. Similarly, means for detecting the connection between thedocking station 200 and the external display 300 is killed has also beenprepared in the standard specifications. In the case of theconfiguration of FIG. 5, there is a DVI_detect signal as one of the DVIsignals. The GPU 114 detects the DVI_detect signal, thereby informingthe BIOS-ROM 120 that the external display unit has been removed.Therefore, in this case, too, it is possible to process an undock event.

While the above-described computer has the DVI connector 204 and hasbeen capable of outputting a signal conforming to the DVI standard, thecomputer may be provided with an HDMI connector in place of the DVIconnector so as to be capable of outputting a signal conforming to theDVI standard.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the inventions. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the inventions. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the inventions.

1. An information processing apparatus comprising: a body configured tobe locked to an external unit by a lock mechanism; a port provided onthe body and configured to output a video signal to the external unit; adisplay controller, provided in the body, that generates the videosignal, and is configured to output the video signal to the port; and acontrol section configured to stop outputting the video signal generatedby the display controller from the port to the external unit, when thelock mechanism is in the unlocked state.
 2. The information processingapparatus according to claim 1, wherein the display controller is tooutput an encrypted video signal.
 3. The information processingapparatus according to claim 2, wherein the encrypted video signal is avideo signal encrypted according to the HDCP standard.
 4. Theinformation processing apparatus according to claim 1, wherein thecontrol section performs control in such a manner that a state where thevideo signal is output to the external unit is shifted to a state wherethe output of the video signal to the external unit is stopped, when thelock mechanism state is shifted from the locked state to the unlockedstate.
 5. The information processing apparatus according to claim 1,wherein the video signal is supplied according to the DVI standard orHDMI standard.
 6. An information processing apparatus comprising: a bodyconfigured to be locked by a lock mechanism to an external unit that isconfigured to output a video signal to an external display unit with adecoder to decode based on an encryption key; a display controller whichis provided in the body and configured to generate a video signalencrypted based on the encryption key; and a control section configuredto output the video signal generated by the display controller to theexternal unit, when the lock mechanism is in the unlocked state.
 7. Theinformation processing apparatus according to claim 6, wherein the videosignal is a video signal encrypted according to the HDCP standard. 8.The information processing apparatus according to claim 6, wherein thecontrol section controls in such a manner that a state where the videosignal is output to the external unit is changed to a state where theoutput of the video signal to the external unit is stopped, when thelock mechanism state is shifted from the locked state to the unlockedstate.
 9. The information processing apparatus according to claim 8,wherein the video signal is supplied according to the DVI standard orHDMI standard.
 10. A video signal output control method in aninformation processing apparatus configured to be locked to an externalunit by a lock mechanism, the video signal output control methodcomprising: detecting the state of the lock mechanism; and stopping theoutput of the video signal to the external unit, when the lock mechanismis in the unlocked state.
 11. The video signal output control methodaccording to claim 10, wherein the video signal is encrypted.
 12. Thevideo signal output control method according to claim 11, wherein theencrypted video signal is a video signal encrypted according to the HDCPstandard.
 13. The video signal output control method according to claim10, wherein the video signal is supplied according to the DVI standardor HDMI standard.
 14. The video signal output control method accordingto claim 10; wherein a state where the video signal is output to theexternal unit is shifted to a state where the output of the video signalto the external unit is stopped, when the lock mechanism state isshifted from the locked state to the unlocked state.